A collection of Exchange servers that have full-time, reliable connections. Messages sent between any two servers within a routing group go directly from source to destination. Routing groups are optional and are not visible in System Manager unless they are enabled.
Change Routing Group Priority
Open Exchange System Manager
Expand Administrative Groups
Expand Routing Groups
Expand First Routing Group
Expand Connectors
Right Click the Desired Routing Group and select Properties
Click the Address Space tab
Double click the text underneath Create, modify, or remove an address space
Set the cost to a lower number for high priority or a higher number for low priority
Change Routing Group Priority